Incendiary grenade



March 28, 1959 L. F. FIESER ET AL. 2,501,766

INCENDIARY GRENADE Filed Feb. 21, 1944 Louis E Fieser eorge C Harris Emanuel B. Henshberg Mar/e Mor ana Freden'cK C. ore/lo SL'earns T. Putnam.

uuw/ S- Patented Mar. 28, 1950 1Louis"FfFieseriBelmont, MassJGeorgeCTHalris, EWilniington, ""DeL, Emanuel *fB. '?Her'shberg, Stoughton; Mass Morley Morgana, Grosse -Pointei MiehiyFrederick C. Novello, Lansdowne, 21221., and-i StearnsiiT. Putnam, Newark, Delgaassisignors tovjthezthrited StatesnfzAmericai-as zrep- :zwesentediv-by itheisecretalymof rWar .t'3LGlaims. 1

' Theinvention-"describew herein may :he manuf a'ctured and =-used =by: :or for the' Government for governmental purposes Without the payment to us -of-any royalty-thereon.

This invention re1ates''partiou'1arly t'o an': inee-ndiarygrenade-adapted? for throwing by hand.

Various incendiarydeviees are known -whiohaoan -he thrown *by "hand, "ejected mechanieally or hurled by a -propellant; and-whichignite through the operation of a fue -mechanism or after impact" on a': target. *The'" "1Vfo1otovcoektai-1" inits crudest'form 'is a glass bottle stiified with c'otton waste soaked in gasoline, which can belighte'd with a match" priortobeing' thrown. "(Dne development consisted the addition-of=aeharge of white phosphor-us :as' an 'igniter, -bt'1t-' this*has the serious disadvantage oft-being slow in action, particularly at i lowtemperatures; and of being unduly "hazardous. Another development -pro- Vided a time fuzei-but this-suffers the-disadvantage that the predetermined fuze time only occasionally coincides *withthe actual: time t of impaet'on a-"target. The -same limitation is:inherent in incendiary grenades 'of "thethermite type. object ofithis invention isto provi'de'afrang'ibie ty-pe grenade-safe-td:hantliefbutwhich;npon receiving a predetermined adequate irnpactf-orce when armed; isj'shattered and. ,efiects iisimultaneoutlyl arelease ofghhemicalgsubstances'jthatiinstantaneouslyi gives aniintensej incendiar aetion.

I Another .obiectof ;this.invention is. to provide an incendiarx grenade which,,.up on recei'yiri wa'dequate impact-whenjarmedris quicktin action even theiignitingo;:fluidinpqnr:adeguate impaet. :Ihe unitiisgso;designedtthatiit eant he. shippedssafelystrid -carried imthe: fieldrwithoutidanger. @When reqniredr ior use, i it Loan :be armed and will giye instant and: positive ignitionwhen impactedoute wa target.

A .su itab1e construction of-ithe-grenade isd-ia- "grammatically illustrated inthe .draW-ing.

Y1 Figure 1 illustrates-a vertical oross se'ction View oi": the-grenade proper.

Figure 2' I illustrates in perspective-' an elevational view of :thegrenade proper in combination andpartial assembly with aprotective casingend cover, the: partial assernbly being shown with ea portion in section.

EFigur-e 3 illustrates a perspeotive VieW'Uf the grenade assembled i withd-its protectiveeasing and cover.

:iR-eferring 1 to the drawing, and particularly' :to Figures landL Z; the Meir-container l-is a g-lass jar having a: volume capacity of about pint to =about-onequart. The container: is: made fromea. frangible material strong enou'gh to resist breakingup to a: certain: point,-=e.- g.,,-az -nti1- dropped 7 reef/onto a hardwoodfioor when fi led.

Attached toithe jar =is=arscrew capil of ordinary commercial "design exceptwfor a small central aperture 3. 'The capmayvbe made of -.any':;materials whichsatisfactorily: resist-ieorrosiomon the inside byithe; fuel and" on:ethe outsidei:byweather- 'ing, e. :"g., acokezplate-i tinned r 0111 15116 insider-and lacquered on the outside i fueleresistantmlastics, andzthe like.

A preferred incendiary :fu'elifillingttkisr a-sgelled =gasolin.e,ifor examp1e,': an'-8:%" to 9% "gel/0f aluminum: soaps in: gasoline, the; soaps (comprising preferably :an aluminumz soap: of saturated fatty acidshaving from' about 8 to: I l-carbonzatomsapermoleculefiogether"withean eaiuminum soap of naphthenictacids and/ormnsaturated fatty-acids Typical formulations for thewpreparationrzof thickeners; and;ge11ing"=agents; areras. follows l partfAluminumi soap. of coconut :oil :acids. or

aluminum lau-rate Lpart-Aluminum n aphthenate 1 partAluminum soap "of coconut oil acids .or

aluminum laurate 1 ;part.Aluminum ;o1eate 2 fip.arts-i-Aluminum :soap of coconut oil v acfdsro aluminumllaurate 1 v part"A1uminum' naphthenate @Agglassizampouleeiischarged-with;-an igniting fluid whichis spontaneouslyinflammable iniair,

This ampoule may be made from two concentric tubes joined as shown by a ring seal at the top; the outer tube being sealed at the narrow bottom tip after the fluid is introduced. The doublewalled ampoule thus has a Dewar bulb form and is hermetically sealed. The igniting fluid 6 is in a space between the two tubes or walls, and the concave side of the inner tube 1 forms a recess. Satisfactory igniting fluids include diethylzinc, triethylboron and other substances, particularly organo-metallic compounds, which remain liquid at about 40 F. and which burst into flame on exposure to air.

The breaking of the ampoule on. impact of the grenade on a target is insured by inclusion of a small hard fracturing body, such as a. steel ball 8 within the recess on the concave side of the inner tube 1. The metal ball 8 of fracturing body is secured in a safe position by a cotter pin 9; and until this pin is withdrawn, there is no danger of breaking the ampoule 5 on accidental jarring or accidental dropping of the unit. When the pin 9 is withdrawn and the grenade thereby deliberately armed, the ball 8 will invariably fracture the ampoule 5 on an adequate impact of the unit, with resulting release of the igniting fluid and ignition of the fuel charge. The ball 8 is mounted at the end of a short section of a fiber tube l0, cemented to the screw cap 2 of the jar container. The ampoule containing the igniting fluid is attached as follows: a section of a fiber tube ll of larger diameter than the outside diameter of the ampoule is cemented to the screw cap placed in an inverted position with the ampoule brought against the inner side of the cap and the annular space between the fiber tube H and the ampoule 5 is filled with methylmethacrylate fluid which is then made to polymerize.

The fracturing member may have shapes other than spherical and may be mounted with other types of safety devices as, for example, with a supporting spring, not shown, having sufficient. strength to resist movement of the fracturing member until adequate impact is given to the unit. For example, the spring may be placed under suitable compression between the steel ball 8 and the bottom of the recess.

The cotter pin 9 which acts as an arming device is inserted through the aperture 3 in the cap 2 and has a looped end I2 protruding above the cap. A pull ring 13 is passed through this loop. The annular space between the cotter pin 9 and the fiber tube l0 may be filled with wax or any suitable soft plastic materialvwhich permits extraction of the cotter pin 9 by pulling on the pull ring I3.

For protection in carrying, the grenade is packed in a metal container or casing M, such as a tin can, with a corrugated paper liner IS. A- tab 56 of strong tape is provided to permit easy withdrawal of the grenade and also to cover the cotter-pin pull ring [3 and thereby prevent the accidental or premature withdrawal of the cotter pin 9. The cover ll, made of tin plate, lacquered black plate, plastic or the like, is held in place on the casing body I4 by an easily removed seal of tape [8. In the packaged condition, the grenade will stand considerable shock and can be handled roughly without concern. It is'not necessarily set oif by rifle fire; for when a bullet hits and shatters the glass ampoule, the igniting fluid, being surrounded by the gasoline gel, does "not come into contact with air to ignite; in a short time the fluid maydissolve in or react chemically with the gelling agent and thereby become protected from contact with air or deactivated.

Even when removed from the case, the grenade is not subject to accidental ignition. If it sustains a severe impact by dropping onto a hard surface, the outer glass jar breaks first and takes up the bulk of the impact force; and the ampoule containing the igniting fluid is thereby spared and remains intact. The ampoule 5 is further cushioned and protected by the surrounding gel 4. Thus it is only when the munition is armed by deliberate 'withdrawal of the cotter pin 9 that the ampoule 5 is at all likely to be fractured. When the arming operation is performed, the fall of the steel ball 8 into the recess is not sufi'icient to break the glass; but the ball is then loose in the recess compartment and will break the ampoule 5 when the grenade is impacted on a target.

The ampoule 5 is constructed of a franglbl material sufliciently strong to resist fracturing until the predetermined minimum impact force is received by the grenade. In general, the ampoule 5 may have thinner walls and less strength than the outer frangible jar container. For example, the .glass wall of the outer jar container I may be from about 1% to inch thick, where'- as the wall thickness of the ampoule 5 may be from about 3 to 3% inch.

A preferred type of incendiary fuel is a gel which is stable throughout a temperature range from 4.0 F. to F. so as to be capable of use in climates ranging from the cold regions of Alaska to the tropics. The gels should have a strong cohesion and stickiness so that when they strike a target, they will adhere and do the greatest damage. A preferred type of incendiary gel for use as a filling in the grenade is described in a copending application, Serial No. 508,632, filed November 1, 1943. This type of gel comprises a mixture of aluminum soaps of saturated fatty acids and aluminum soaps of naphthenic and/or unsaturated fatty acids. In addition to the soaps, the gelled gasoline may contain other substances such as lamp black or wood flour; Other gelled, thickened or solidified fuels may also be used, such as mixtures of combustible oils with rubber or with synthetic high molecular weight linear polymers, e. g., isobutylmethacrylate, polybutene and the like. I The thickened, gelled or solidified fuel filling may be modified to accelerate its ignition, particularly when it is to be used in a. grenade at extremely low temperatures. To accomplish this modification, additives of certain low fire point substances may be used, e. g., nitrated alcohols, peroxides, poly-, sulfides, free sulfur, and aliphatic ethers. Such additives need not be too volatile and may be safely mixed with the fuel.

The grenade will withstand indefinite immersion in water or exposure to the most severe conditions of high humidity. It functions fully satisfactorily at all operational temperatures, even over the range from -40 F. to 150 F. The igniter, being sealed in glass, is subject to no deterioration whatsoever under any conditions or time of storage. The complete unit can be shipped with little danger. An alternate scheme which provides still greater security is to ship the unit without gasoline but with the proper amount of Napalm or other solid thickening agent in the glass jar. Just before use, the cap may be unscrewed and the jar filled with gasoline.

Then" the cap may be put in place and the unit shakeir and given a few minutes to allow for gelation. The grenade has many tactical uses. When thrown against a wall or other hard surface, the grenade forms a wide splatter of flaming sticky gel which adheres to the target and exerts a very efficient incendiary effect. Thus the unit is well adapted for use in demolishing factory buildings, warehouses or dwellings. It is also a very efiective anti-tank weapon. A hit somewhere near either the turret or the air intake of a hostile tank can be very destructive. The gel will adhere to the metal surface and will continue to burn for several minutes. The flames can thus be drawn into the tank with resulting attrition of the crew, stoppage of the motor or combustion of lubricating oil in the revolving turret. The grenade is conveniently set for action since it can be promptly armed and can be of convenient size for throwing by hand. At the instant the grenade strikes the target, its incendiary action is begun, and the incendiary fuel remains on the target.

It is to be understood that although the invention has been described with reference to specific preferred embodiments, other modifications come within the spirit and scope thereof.

What is claimed is:

1. An incendiary grenade comprising in a frangible container a carbonaceous fuel, a hermetically sealed glass bulb charged with an igniting fluid which remains liquid at temperatures as low as about -40 F. and which bursts into fiame or exposure to air, a ball wholly within said container and intermediate of said bulb and said container for fracturing said glass bulb on adequate impact of the grenade, when resistance to movement of the body is removed, and a flexible bifurcated metal means for holding said ball and preventing said ball from breaking said bulb until the grenade is deliberately armed and receives an adequate impact.

2. An incendiary device adapted for instantaneous ignition upon impact with adequate force, comprising a glass container filled with a sticky gelled gasoline, a separate hermetically sealed glass ampoule having a re-entrant portion charged with an igniting fluid which is spontaneously inflammable in air, said ampoule being substantially immersed in the gelled gasoline, a metallic bifurcated supporting means secured to said container and extending into said re-entrant portion, and a glass-fracturing body detachably mounted in said re-entrant portion on said supporting means wholly within said container and secured with relation to the ampoule in a safe position to avoid fracturing the ampoule until said body is released into an armed position and the grenade receives a predetermined adequate impact.

3. An incendiary grenade comprising a glass jar, a screw cap cover for the jar, said screw cap covering having an aperture, a cotter pin fastener having a looped end protruding above the cover and projecting through the aperture of the cover into the jar, a steel fracturing member detachably secured to said fastener, a glass ampoule having a Dewar bulb form, said ampoule hermetically inclosing a liquid organo-metallic incendiary compound which ignites spontaneously in air, a plastic seal attaching said ampoule to the cover with the ampoule providing a recess space for inclosing said steel fracturing member mounted on a bent end of the cotter pin, and a pull ring passed through the looped end of the cotter pin above the cover for manipulation in arming the grenade by removal of the cotter pin.

LOUIS F. FIESER. GEQRGE C. HARRIS. EMANUEL B. HERSHBERG. MORLEY MORGANA. FREDERICK C. NOVELLO. STEARNS T. P'UTNAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS I Name 

